It is one of the great British films, superbly made and tremendously powerful, so it is not surprising that Zulu, released 50 years ago, takes a close interest in social class. A key secondary theme in the film is the uneasy relationship between the two lieutenants leading the defence of the mission station at Rorke's Drift. One is an infantry officer, Gonville Bromhead, blond and foppish, played by Michael Caine, and the other a slightly older, gruff Royal Engineer called John Chard (Stanley Baker). Class is what fuels the friction, and this is made explicit in the dialogue, with plenty of "chin, chin"s and "old boy"s de haut en bas from toffee-nosed Bromhead to Chard.

It was Caine's first major role; he is "introduced" in the credits. (Amazing to think now that the role he was originally down for was Private Henry Hook, memorably played by James Booth, which would have required a Cockney accent.) It required him (a former Smithfield porter) to abandon his distinctive vowels and talk posh – with only partial success. But the thing is – it doesn't matter a bit. We accept him. Like Clark Gable, who refused under any circumstances to do a southern accent in Gone with the Wind, Caine succeeds through the sheer force of his personality – proving he was a proper film star, not just an actor.

Here is the famous scene where Bromhead and Chard first meet (go to 18 minutes):